How to implement sub-numbering for custom figures and equations?

Questions
,
1

After reading a post here about this topic for equations where the first number of the numbering should be from the level 1 heading I found this solution:

#set heading(numbering: "1.")
#show heading.where(level:1): it => {
  counter(math.equation).update(0)
  it
}

#set math.equation(
  numbering: it => {
    let count = counter(heading.where(level: 1)).at(here()).first()
    if count >0 {
      numbering("(1.1)", count, it)
    } else {
      numbering("(1)",it)
    }
  }
)

How I can implement it also for this custom figure (theorem):

#show figure.where(kind: "thm"): it => [
  / #it.supplement #context(it.counter.display(it.numbering)).: #it.body
]
#let thm(it) = figure(
  kind: "thm",
  supplement: "Theorem",
  caption: none,
  placement: none, 
  it
)

What will be the most correct way to implement a thing like this? Any tips on making this numbering function to be more generic or to define the theorem better would help a lot!

2

Setting the kind argument will automatically generate a counter. I learned a bit more since the last post (e.g., .get() is the same as .at(here())).

#set heading(numbering: "1")

#show heading.where(level:1): it => {
  counter(figure.where(kind: "thm")).update(0)
  it
}

#show figure.where(kind: "thm"): it => {
  let num = numbering(
    "1.1",
    counter(heading).get().first(),
    it.counter.get().first()
  )
  [/ #it.supplement #num: #it.body]
}

#let thm(it) = figure(
  kind: "thm",
  supplement: "Theorem",
  // default values of caption & placement are already none :)
  it
)


= one chapter

#thm(lorem(20))
#thm(lorem(20))
#thm(lorem(20))
#thm(lorem(20))

= another chapter

#thm(lorem(20))
#thm(lorem(20))
#thm(lorem(20))
#thm(lorem(20))

Follow-up question though… I had never seen the [\ text:] styling before for bolding. Where is that from? Is it just another way to bold text?

3

@miles-1 The slash syntax is for term lists.

@Ido As you may already know, there are packages like great-theorems which take care of all of this.

1 Like
4

Hey @Ido! I’ve changed your question post’s title to better fit our guidelines: How to post in the Questions category

For future posts, make sure your title is a question you’d ask to a friend about Typst. :wink:

1 Like
5

Thanks a lot! I am having some rough time adding the if statement to this implementation for the figure numbering… any help on that?

6

If I’m understanding your initial code correctly, you want to make all theorems before the first header just have a theorem counter number (e.g., (1)), and all theorems after a header to have that header’s number and the theorem counter number (e.g., (1.1)), yes? If that’s the case, inside your show rule for thm figures, you will want to:

  • save current header count in a variable (e.g., let header_count = ...)
  • save current theorem count in a variable (e.g., let thm_count = ...)
  • use an if statement to use one of the two numbering uses based on header_count, and save its result to a variable (e.g., let num = if header_count > 0 {...} else {...})

Give that a try!

7

Something like this?

#show figure.where(kind: "thm"): it => {
    let header_count = counter(heading.where(level: 1)).get().first()
    let thm_count = it.counter.get().first()
    let thm_num = if header_count > 0 {
      numbering("1.1.",header_count,thm_count)
    } else {
      numbering("1.",thm_count)
    }
    set align(left)
    terms[/ #it.supplement #thm_num: #it.body]
}

Thanks a lot!!

1 Like